Submicrometer particle formation and control in a bench-scale pulverized coal combustor

Experimental studies were performed to investigate the formation mechanisms of submicrometer particles during combustion of a pulverized Ohio bitumino us coal. Elemental compositions of total and submicrometer ash and particle size distributions were measured at different operating conditions. The su bmicrometer ash particles were formed by means of a vaporization-nueleation -condensation mechanism. A decreasing collection efficiency in a cylindrica l. electrostatic precipitator was observed for ash particles smaller than 1 00 nm due to insufficient charging. A vapor-phase sorbent injection methodo logy was used in the coal combustion system, and was shown to suppress the nucleation mode of the ash particles.